Judges 16:8

Then the lords of the Philistines brought up to her To the chamber where she was with Samson, she having acquainted them with what he had told her:

seven green withs, which had not been dried; just such as he had described and directed to:

and she bound him with them; taking an opportunity, very likely, when he was asleep, and drunk too, according to Josephus F24: the Philistines did not attempt to bind him, supposing that he would not admit them to do it, if aware of them; and they might fear, if asleep, he might awake before they could do it, and fall upon them and destroy them; but as for Delilah, if she had been found at it, she could have excused it as a piece of curiosity, being willing to try whether he told her truth or not.